1. Field of the Invention
The present invention relates to a process for the manufacturing of surface elements with a decorative upper surface of which the decorative elements have an considerably improved matching of the dxc3xa9cor between adjacent surface elements.
2. Description of the Related Art
Products clad with thermosetting laminate is common in many areas nowadays. They are mostly used where the demands on abrasion resistance are high, and furthermore where resistance to different chemicals and moisture is desired. As examples of such products floors, floor skirtings, table tops, work tops and wall panels can be mentioned.
The thermosetting laminate most often consist of a number of base sheets with a decor sheet placed closest to the surface. The decor sheet can be provided with a pattern by desire. Common patterns usually visualise different kinds of wood or mineral such as marble and granite.
One common pattern on floor elements is the rod pattern where two or more rows of rods of, for example wood, is simulated in the dxc3xa9cor .
The traditional thermosetting laminate manufacturing includes a number of steps which will result in a random matching tolerance of up to xc2x15 mm, which is considered too great. The steps included in the manufacturing of a laminate floor is: printing decor on a paper of xcex1-cellulose, impregnating the decorative paper with melamine-formaldehyde resin, drying the decorative paper, laminating the decorative paper under heat and pressure together with similarly treated supporting papers, applying the decorative laminate on a carrier and finally sawing and milling the carrier to the desired format. All these steps in the manufacturing will cause a change in format on the decor paper. It will, therefore, be practically impossible to achieve a desired match of patterns between adjacent elements causing great amounts of wasted laminate. Naturally, this waste is not desirable, as the thermosetting laminate is a rather costly part of a laminate floor.
It has, through the present invention, been made possible to overcome the above mentioned problems and provide a surface element with a decorative surface where the decorative pattern between different surface elements with matching of the decorative pattern can be obtained. The invention relates to a process for the manufacturing of surface elements which surface elements comprise a decorative upper layer and a support core. The surface elements may be used as floor, wall or ceiling boards. The invention is characterised in that:
i) A supporting core with a desired format is manufactured and provided with an upper side and a lower side.
ii) The upper side of the support core is then provided with a dxc3xa9cor , by, for example, printing. The dxc3xa9cor is positioned after a predetermined fixing point on the support core.
iii) The upper side of the supporting core is then provided with a protecting, at least partly translucent, wear layer by, for example, spray coating, roller coating, curtain coating and immersion coating or by being provided with one or more sheets of xcex1-cellulose impregnated with thermosetting resin or lacquer.
The dxc3xa9cor is suitably achieved by digitisation of an actual archetype or by partly or completely being created in a digital media. The digitised dxc3xa9cor is stored digitally in order to be used as a control function and original, together with possible control programs, when printing the dxc3xa9cor.
The dxc3xa9cor may accordingly be obtained by making a high resolution or selected resolution digital picture of the desired decor. This is suitably made by means of a digital camera or scanner. The most common dxc3xa9cor will of course be different kinds of wood and minerals like marble, as these probably will continue to be preferred surface decoration in home and public environments. It is, however, possible to depict anything that is visible. The digitised version of the dxc3xa9cor is then edited to fit the size of the supporting core. It is also possible to rearrange the dxc3xa9cor in many different ways, like changing colour tones, contrast, dividing the dxc3xa9cor into smaller segments and adding other decorative elements. It is also possible to completely create the dxc3xa9cor in a computer equipped for graphic design. It is possible to create a simulated dxc3xa9cor so realistic that even a professional will have great problems in visually separating it from genuine material. This makes it possible to make for example floor boards with an almost perfect illusion of a rare kind of wood, like ebony or rose wood and still preserving trees under threat of extermination.
The digital dxc3xa9cor is used together with guiding programs to control a printer. The printer may be of an electrostatic type or an ink-jet type printer. Most often the colours yellow, magenta, cyan and black will be sufficient for the printing process, but in some cases it might be advantageous to add white. Some colours are difficult to achieve using the colours yellow, magenta, cyan, black and white whereby the colours light magenta and light cyan may be added. It is also possible to add so called spot colours where specific colour tones are difficult to achieve or where only certain parts of the colour spectrum with intermixing shades is desired. The resolution needed is much depending on the dxc3xa9cor that is to be simulated, but resolutions of 10-1500 dots per inch (dpi) is the practical range in which most dxc3xa9cors will be printed. Under normal conditions a resolution of 300-800 dpi is sufficient when creating simulations of even very complex decorative patterns and still achieve a result that visually is very difficult to separate from the archetype without close and thorough inspection.
The digitally stored dxc3xa9cor can also be used together with support programs when guiding other operations and procedures in the manufacturing process. Such steps in the operation may include procedures like identification marking, packaging, lacquering, surface embossing, storing and delivery logistics as well as assembly instructions.
It is advantageous to manufacture the supporting core in the desired end user format and to provide it with edges suited for joining before applying the dxc3xa9cor and wear layer, since the amount of waste thereby is radically reduced. The dxc3xa9cor matching tolerances will also be improved further by this procedure.
The main part of the support core is suitably constituted by a particle board or a fibre board. It is, however, possible to manufacture the core that at least partly consists of a polymer, such as, for example, polyurethane or a polyolefin, such as, polyethylene, polypropylene or polybutene. A polymer based core can be achieved by being injection moulded or press moulded and can be given its shape by plastic moulding and does, therefore, not require any abrasive treatment. A polymer based core may also contain a filler in the form of a particle or fibre of organic or inorganic material, which, besides its use as a cost reducing material, also can be used to modify the mechanical characteristics of the core. As an example of such suitable fillers can be mentioned; cellulose or wood particles, straw, starch, glass, lime, talcum, stone powder and sand. The mechanical characteristics that may be changed are, for example, viscosity, thermal coefficient of expansion, elasticity, density, fire resistance, moisture absorption capacity, acoustic properties, thermal conductivity, flexural and shearing strengths as well as softening temperature.
The upper surface, i.e. the surface that is to be provided with dxc3xa9cor, is suitably surface treated before the printing. Such surface treatment will then incorporate at least one of the steps, ground coating and sanding. It is also possible to provide the surface with a structure that matches the dxc3xa9cor that is to be applied.
The translucent wear layer is suitably constituted by a UV- or electron beam curing lacquer such as an acrylic,epoxy, or maleimide lacquer. The wear layer is suitably applied in several steps with intermediate curing where the last one is a complete curing while the earlier ones are only partial. It will hereby be possible to achieve thick and plane layers. The wear layer suitably includes hard particles with an average particle size in the range 50 nm-150 xcexcm. Larger particles, in the range 10 xcexcm-150 xcexcm, preferably in the range 30 xcexcm-150 xcexcm, are used to achieve abrasion resistance while the smaller particles, in the range 50 nm-30 xcexcm, preferably 50 nm-10 xcexcm is used for achieving scratch resistance. The smaller particles is hereby used closest to the surface while the larger ones are distributed in the wear layer. The hard particles are suitably constituted of silicon carbide, silicon oxide, xcex1-aluminium oxide and the like. The abrasion resistance is hereby increased substantially. Particles in the range 30 mm-150 mm can for example be sprinkled on still wet lacquer so that they at, least partly, become embedded in the finished wear layer. It is therefore suitable to apply the wear layer in several steps with intermediate sprinkling stations where particles are added to the surface. The wear layer can hereafter be cured. It is also possible to mix smaller particles, normally particle sizes under 30 xcexcm with a standard lacquer. Larger particles may be added if a gelling agent or the like is present. A lacquer with smaller particles is suitably used as top layer coatings, closer to the upper surface. The scratch resistance can be improved by sprinkling very small particles in the range 50 nm-1000 nm on the uppermost layer of lacquer. Also these, so called nano-particles, can be mixed with lacquer, which with is applied in a thin layer with a high particle content. These nano-particles may besides silicon carbide, silicon oxide and xcex1-aluminium oxide also be constituted of diamond.
According to one embodiment of the invention, the translucent wear layer is constituted of one or more sheets of xcex1-cellulose which are impregnated with melamine-formaldehyde resin. These sheets are joined with the core under heat and pressure whereby the resin cures. It is, also in this embodiment, possible to add hard particles with an average particle size in the range 50 nm-150 xcexcm. Larger particles, in the range 10 xcexcm-150 xcexcm, preferably 30 xcexcm-150 xcexcm, is foremost used to achieve abrasion resistance while the smaller of the particles, in the range 50 nm-30 xcexcm, preferably 50 nm-10 xcexcm, is used to achieve scratch resistance. The smaller particles is hereby used on, or very close to, the top surface while the larger particles may be distributed in the wear layer. Also, here the particles advantageously are constituted of silicon carbide, silicon oxide, xcex1-aluminium oxide, diamond or the like of which diamond, for cost reasons only is used as particles smaller than 1 xcexcm. The sheets of xcex1-cellulose is hereby suitably pressed together with the rest of the surface element in a continuous belt press with two steel belts. The pressure in the press is hereby suitable 5-100 Bar, preferably 20-80 Bar. The temperature is suitably in the range 140-200xc2x0 C. It is also possible to utilize a discontinuous process where a number of surface elements can be pressed in a so called multiple-opening press at the same time. The pressure is then normally 20-150 Bar, preferably 70-120 Bar, while the temperature suitably is 120-180xc2x0 C., preferably 140-160xc2x0 C.
The dxc3xa9cor on the surface elements is suitably constituted by a number of dxc3xa9cor segments with intermediate borders, which borders, on at least two opposite edges coincide with intended, adjacent surface elements.
It is also desirable to provide the surface elements with a surface structure intended to increase the realism of the dxc3xa9cor of the surface elements. This is suitably achieved by positioning at least one surface structured matrix, forming at least one surface structure segment on a corresponding dxc3xa9cor segment or number of dxc3xa9cor segments on the decorated surface of the surface element in connection to the application of wear layer. This matrix is pressed towards the wear layer whereby this will receive a surface with structure that enhances the realism of the dxc3xa9cor.
When simulating more complex patterns, like wood block chevron pattern or other dxc3xa9cors with two or more divergent and oriented dxc3xa9cors, it is suitable to use at least two structured matrixes which forms one structure segment each. The structure segment are here independent from each other in a structure point of view. The surface structure segments are intended to at least partly but preferably completely match the corresponding dxc3xa9cor segments of the dxc3xa9cor. The surface structure segments are accurately positioned on the dxc3xa9cor side of the surface element in connection to the application of the wear layer, and is pressed onto this whereby the wear layer is provided with a surface structure where the orientation of the structure corresponds to the different directions in the dxc3xa9cor.
One or more matrixes preferably forms the surface of one or more rollers. The surface element is then passed between the roller or rollers and counter stay rollers, with the dxc3xa9cor side facing the structured rollers. The structured rollers are continuously or discontinuously pressed towards the dxc3xa9cor surface of the surface element.
Rollers containing two or more matrixes, is suitably provided with a circumference adapted to the repetition frequency of change of direction in the dxc3xa9cor.
It is also possible to apply the structure matrixes on the surface of a press belt. The surface element is then passed between the press belt and a press belt counter stay under continuous or discontinuous pressure between the structured press belt and the press belt counter stay.
It is, according to one alternative procedure, possible to have one or more matrixes form the structure surface of one or more static moulds which momentary is pressed towards the decorative side of the surface element.
According to one embodiment of the invention, particularly characteristic dxc3xa9cor segments such as borderlines between simulated slabs, bars, blocks or the like and also knots, cracks, flaws and grain which is visually simulated in the dxc3xa9cor, are stored as digital data. Said data are used for guiding automated engraving or pressing tools when providing said characteristic dxc3xa9cor segments with a suitable surface structure, and that said engraving tool or pressing tool is synchronised via the predetermined fixing point on the surface element.
The process described in the present application, for manufacturing surface elements is very advantageous from a logistic point of view since the number of steps when achieving a new dxc3xa9cor is radically reduced. It is, according to the present invention possible to use digitally created or stored data for directly printing the dxc3xa9cor on a surface element by using a ink-jet printer or a photo-static printer. The so-called set up time will thereby be very short, whereby even very special customer requirements may be met at a reasonable cost. It is according to the present invention possible to manufacture, for example, a world map in very large format, stretching over a great number of surface elements without any disrupting deviations in dxc3xa9cor matching, to mainly the same cost as bulk produced surface elements. Since the dxc3xa9cor may be handled digitally all the way to the point of being applied to the surface of the core, set up times will be practically non-existent while at the same time a high degree of automation will be practicable. It is also possible to automatically provide the surface elements with identification and orientation marking which would make the installation of complex dxc3xa9cors, like world maps in the example above, much easier. This has so far been impossible.
The dxc3xa9cor on the surface elements may be processed as follows;
i) A segmentation pattern is selected, the segmentation comprising at least two dxc3xa9cor segments on each surface element. The shape, as seen from above, of the surface element is hereby selected from the group; triangular, quadratic, rectangular, heptagonal, pentagonal and octagonal while the shape of the segments is selected from the group triangular, quadratic, rectangular, heptagonal, pentagonal, octagonal, circular, elliptical, perturbed and irregular.
ii) A segment dxc3xa9cor is then selected for each segment. The segment dxc3xa9cor is selected from the group; digitised and simulated depiction of different kinds of wood, minerals and stone, different kinds of fabric, art work and fantasy based dxc3xa9cor.
iii) Each selection is made on a terminal where the selections emanates from a data base and that the selection is visualised via the terminal.
The dxc3xa9cor is preferably achieved by digitisation of an actual archetype or by partly or completely being created in a digital media. The digitised dxc3xa9cor is preferably stored digitally in order to be used as a control function and original, together with control programs and selection parameters, when printing the dxc3xa9cor.
The dimensions of the surface to be covered by surface elements is suitably entered into the terminal and support programs calculates an installation pattern. The installation pattern calculation is suitably also used for printing an assembly instruction. In order to visualise the selection the installation pattern calculation is possibly used for printing a miniaturised copy of the calculated installation with the selected pattern and dxc3xa9cor. The dimensions of the surface to be covered by surface elements is suitably entered into the terminal and that that support programs further calculates dxc3xa9cor and segmentation pattern matching between the surface elements.
The selections is preferably also used, together with support programs for controlling further steps in the manufacturing procedure selected from the group; identification marking, positioning marking, packaging, lacquering, surface embossing, storing and delivery logistics.
An algorithm is suitably used for guiding the positioning of the dxc3xa9cor segments and segmentation pattern so that a dxc3xa9cor segment from one surface element may continue on an adjoining surface element. The control program is suitably used, together with dxc3xa9cor data and selection parameters, for applying matching identification on the surface elements.
Surface elements manufactured as described above is suitably used as a floor covering material where the demands on stability and scratch and abrasion resistance is great. It is, according to the present invention, also possible to use the surface elements as wall and ceiling decorative material. It will however not be necessary to apply thick wear layer coatings in the latter cases as direct abrasion seldom occurs on such surfaces.
The invention is described further in connection to an enclosed FIGURE, embodiment examples and schematic process descriptions showing different embodiments of the invention.